Modified handleEndOfLine to make sure doesn't return an empty RenderInline. Also added an assert to setLineBreakObj to make sure the line break isn't set to an empty inline.

BUG=305904

Review URL: https://codereview.chromium.org/42803002

git-svn-id: svn://svn.chromium.org/blink/trunk@161533 bbb929c8-8fbe-4397-9dbb-9b2b20218538